Insect repellent



Patented July 4, 1939 UNITED STATES 2.104.321; msac'r REPELLENT mi ic a. nay, St. Louis, Mo., santo Chemical Company, St. poration oi'llelaware No Drawing. Application December 10,

assignor to Mon- Louis, Mo., a cor- Serial No. 756.827

5 Claims. (oi. 21-43) This invention relates to the control of insects by means of repellents and it has particular relation to the use of repellents for such wood burrowing insects as ambrosia beetles, termites, powderpost beetles, roundhead borers, marine borers of the type of Limnoria, Teredo, etc., and similar cellulose destroying or eating insects.

The main objects of the invention are to provide a repellent for insects of the above indicated classes; which is characterized by low costs, both .for materials and for the application thereof; which is highly repellent to insects; relatively permanent upon application to wood; free from odors objectionable to man; non-toxic to higher forms of animal life; does .not pose the wood to which it is applied, or varnishes or paints which are subsequently applied to the wood; may be dissolved in inexpensive solvents and/or emulsifying agents and which does not materially increase fire hazards upon application to wood. These and other objects will be apparent from perusal of the appended specification.

It is well known that the agencies of destruction for wood, aside from fire, are decay and the attacks of burrowing insects. The insects, of course, weaken the wood by reason of the destruction of the fiber thereof in the formation of their tunnels. They also carry fungi and spores of fungi which occasion sap stain and decay, thereby inoculating the unin: fected wood and causing premature degeneration or destruction thereof.

It has heretofore been proposed to control the ravages of these insects by treating the wood with various chemicals. However, no material entirely satisfactory for posed because such material must simultaneously possess a relatively great number of peculiar and in some'cases paradoxical characteristics. For example, the material must be highly repellent to insects, not only of the type which actually take the wood into their digestive system but also to those, such as the ambrosia beetle, which burrow through bark and wood without actual digestion thereof. These latter, of course, require a material which, through odor or some other mode of reaction upon the senses of the beetles, acts as a repellent and prevents them from entering the wood. The material must further be free from odors objectionable to man and of no, or at least slight, toxicity to higher forms of animal It must be relatively non-volatile and retain its repellent characteristics for a relatively long period of time, Also, it should not stain or otherwise damage the wood to which it is applied. Preferably it should be soluble or at least readily emulsifiable in common and inexpensive solvents, still it must withstand out-of-door exposure conditions. Furthermore, it should be relatively in-.

two principal natural stain or decompetroleum ether,

this purpose has been prolife.

expensive both to obtain and to apply. No material has heretofore been obtained which possessed all of these desirable characteristics in adequate degree.

This invention involves the discovery that polyaryl hydrocarbons containing two or more aryl nuclei joined together, either directly or by means of a hydrocarbon linkage, are especially well adapted for the purpose above outlined. Diphenyl is a specific example of satisfactory member of this class of materials. However, other similar-materials, including dibenzyl, triphenyl, ditolyl, dinaphthyl, diphenylmethane, diphenylethane, triphenylmethane, etc. may also be employed. The value of these compounds as repellents for wood boring organ isms is'surprising because diphenyl has heretofore been tested as a moth-proofing agent (German Patent 504,886) and found to be of no worth. Moreover, such closely related materials as naphthalene and kerosene are ineffective (United States Department of Agriculture Bulletin No. 1079, page 8).

In the use of the compounds contemplated herein, a solution in a convenient solvent may be employed. A relatively large number of these are available including gasoline, benzene, toluene,

alcohol, heavier oils of the lubricating grade, kerosene, etc. In some cases where the more volatile solvents (benzene or gasoline) are employed it is also desirable to incorporate a relatively non-volatile resin or wax, such as rosin or paraffin, in an amount approximately equal to the repellent, into the solvent for purposes of preventing unduly rapid evaporation and resultant deposition of flufly crystals of the repellent upon the surface of the wood.

For purposes of preventing the attack of ambrosia beetle upon green logs or lumber the repellent may be employed in various concentrations. However, approximately one to three pounds of diphenyl per thousaid board feet are quite satisfactory. This material may be made up into a solution with benzol in the concentration of about 1.5 pounds per gallon of benzol. In the case of green logs it should be applied over the bark by spraying or by dipping the logs in a vat or other container charged with the solution'of the repellent. In case application is made by spraying, the ends of the logs should also be covered in order to prevent entrance of beetles parallel to the grain of the wood.

Ambrosia beetles are especially numerous in the south and are most destructive to the freshly .cut logs or to timber prepared therefrom, making burrows through the wood and infecting the ad-" comparatively immune from the attacks of these insects, and as the repellent retains its activity over a period of thirty or sixty days a single application is generally suflicient permanently to prevent the attacks of the beetles.

The repellent action of the material also makes it ideal for application to lumber in a stack. It may be applied to the lumber by spraying the exterior of the stack to prevent the parent beetles from lighting thereupon for purposes of burrowing and depositing their eggs.

Some of the other forms of beetles, i. e. powderpost or Lyctus, roundhead beetles, also actively attack dry timber and lumber. Accordingly, to preserve logs or lumber therefrom over long periods of time it is necessary ,to make application of the repellent at intervals. The repellents are effective in protecting various species of wood including pine, spruce, gum, etc.

To illustrate the eiiiciency of my invention the results of a typical series of comparative tests thereof with certain common repellents are given. In these tests a series of gum logs (four or five per compound tested) were sprayed heavily with a solution of the repellent, and

' after a period of time a count was made to determine the number of insects which had attacked the logs.

Avegnge Compound tested a ga i f per log Beta naphthol 6. 2 Cresylic acid 20 Ortbodichlorbenzene. 6 Paradichlorbenaene 6 Trichlorbenzene 20 Chlorinated diphenyl 42% combined claim-in 15 Chlorinated diphenyl 54% combined chlorine" Cyclohaxylamino 8 Benzyl plienol. 25 Untraawd contro 12 Diphenyl. o, 5

In these experiments care was observed to insure that the application of diphenyl was less than or at least not greater than that or the repellents with which it was compared.

If the repellent is employed against marine borers of the type of. Teredo, it should be dissolved in heavy oil, for example, of lubricating grade. Diphenyl and the other materials herein listed are also suitable for impregnation of woods. Any of the standard methods may be employed to introduce the ingredient into the wood. For example, it may first be subjected to vacuum to exhaust the cells of the wood and then to pressure under the treating fluid to fill them therewith For purposes of impregnation about one and one-half pounds of diphenyl or other repellent should be employed per cubic foot of wood. The solvents and the concentrations employed may be the same as employed for spraying or dipping.

Some insects, including termites, have their burrows under the soil and from there they travel to any wood available. Houses and similar buildings may be protected from the ravages of these pests by direct application of the above described repellents. They may also be combatted by soil poisons deposited in trenches about the structures. Preferably a trench two or three inches deep is dug about and close to the foundation of the structure and the repellent is de- 2,re4,saa

-posited therein. Diphenyl may be employed in dry state in amounts of two to four pounds per ten linear feet "of trench. It may also be dissolved in a solvent in an'amount of say two pounds per gallon and applied in. an amount or one or two gallons per ten linear feet of trench. The trenches may be filled with loose earth after addition of the repellent.

It is to be understood that the polyaryl hydrocarbons contemplated by the present invention may be used alone, as is described above, or in conjunction with other materials which are known to be valuable for other cellulose damaging organisms or agents. Thus, for example, polychlorphenols may be included with the aryl hydrocarbon repellent to control sap stain in the manner well understood by those engaged in the timber industry. It is likewise to be understood that whereas the material may be applied as a solution in an organic solvent one may, it desired, apply the material as a suspension or emulsion. In either case tne use of agglutinants to insure the adhesion of the repellent, as is well understood by those skilled in'this art, comes within the scope of. the present invention.

The polyaryl hydrocarbons of this invention are highly emcient as repellents of insects of the ambrosia beetle type and other wood boring insects. At the same time they are readily available and may be dissolved in relatively high concentration in inexpensive solvents. They are non-toxic to man and the odor thereof is slight and comparatively unobjectionable, Their application does not occasion staining of the wood and the fire hazard is not increased. Accordingly, they are highly desirable from a commercial viewpoint.

Reference is made to my co-pending divisional application, Serial No. 243,139, filed on November 30, 1938, which contains subject matter disclosed but not claimed herein.

Although I have shown and described the preferred forms of the invention it will be apparent that numerous modifications may be made therein without departure from the spirit of the invention or'the scope of the appended claims.

-What I claim is:

1. The method of protecting green logs and green lumber from attack by wood boring insects of the beetle type which comprises applying to the surface of said logs and lumber a polyphenyl material selected from the group consisting of diphenyl and triphenyl.

2. The-method of protecting green logs and green lumber from attack by wood boring insects of the beetle type which comprises applying diphenyl to the surface of said logs'and lumber. I

3. As a repellent for insects of the beetle type which normally attack green logs and green lumber, a polyphenyl selected from the group consisting of diphenyl and triphenyl.

4. As a repellent for insects of the beetle type which normally attack green logs and green lumber, a diphenyl hydrocarbon.

5. The method of protecting green logs and green lumber from attack by the Ambrosia beetle which comprises applying to the surface of. said logs and lumber a polyphenyl material selected from the group consisting of diphenyl and triphenyl.

HAROLD R. HAY. 

